Cosmic evolution through UV surveys (CETUS): point spread function analysis of three mirror anastigmat telescope

From studying the fossil records of stars to exploring the circumgalactic medium, UV astronomy is a field rife with scientific opportunity. CETUS is a proposed next-generation UV space telescope equipped with a suite of instruments tailored to the study of UV phenomena in our galaxy. To achieve diffraction-limited imaging and spectroscopy performance at short wavelengths, a high-performance and resolution optical design is necessary. We describe the telescope design options including a trade study between a traditional on-axis TMA and freeform off-axis TMA solution considering their alignment sensitivity and tolerances. Different secondary support structures are explored for the on-axis design to analyze the irradiance distribution of the point-spread function (PSF) due to the pupil obscuration and how it influences the simulated starfield at the telescope focal planes. With rigorous analysis we aim to enable the next spaceborne observatory for UV astronomy.